Would anyone out there in timber frame land choose to share their favorite methods/templates for cutting housings, particularly blind housings with a router.

I am on my 5th frame, the first 3 being fully scribed but have just finished my first square rule frame and have another on the books. Quite frankly cutting blind housings with a chisel is driving me mad. It is the sort of job machines were made for.
I have tried playing around with a square cutting bit with the router held free hand but am not happy with the level of control. I have had a bit of a look at router jigs out there and they all seem to rely on using the base as a guide.
To me a pattern cutting bit with a template the same size as your housings makes the most sense.
Are there off the shelf, adjustable pattern cutting jigs out there? Do you make your own? Do you have a separate jig for each standard housing you cut?
Would love to hear your ideas.

The problem with using the bearing bit is that the router rides on the surface of the timber, which may be rough, uneven, or not parallel to your reference face. We use jigs with a masonite bottom. The walls are the guide. The downside is that it will only work with a specific router. Find more details on this web page.

I have a festool router jig with a slide attachment. Totally acurate ajustment. It's pretty expensive so I used it to make housing jigs with 5/8 baltic birch ply. That way if a bearing fails or I have a brain fart I just make a new one. What I did was make all common widths but larger lengths. I have various inserts I use to bring the jig down to the various beam heights. That way I need less jigs and can make inserts with the miter saw. As far as uneven posts or cupped, crowned checked posts, the 5/8 is thick enough to stay pretty straight (flat). I use a mafell lo65 2200 router with a 1" bit with a template guide. That way I dont rely on the bearing much and the jig can be used for slightly undersized timber because the template guide will cut 7-3/8" wide on the 7-1/2" jig. I use a long shafted bit with a short depth of cut with more than one bearing on it
with this setup I can cut deep or shallow housings with the same bit/router.if I want to be sure to cut exactly the width of the jig instead of the 1/8" slim, I just set the router on another piece of birch ply with a hole for the template guide to drop in with the bearings sitting below the plywood slide so it bears on the housing jig edge. Then I just take that last slice off. I use the festool router slide to hog out the housing because it is thin enough for the template guide to drop through. Works great. On one plywood housing jig insert for each width size, I have a "plug" attatched to drop in the mortise so the housing is set exactly with the mortise without layout inaccuracies.

Do you have to do additional chisel work after the router? Example scoop the bottom of the housing to allow for drying and shrinkage?

TimBeal - I would pare the end grain on tenon shoulders instead of trying to scoop out housings, being sure to keep bearing and mating surfaces flat and square to the layout, but essentially undercutting the shoulder or 'scooping out' as you say. Easier to do that than hollow out housings that do not come to the edge of the timber. This was slick work for me, prior to labeling and end sealing. Last step on nearly every tenon.

The housing is very flat, if the timber is crowned across the grain due to checking etc. one can use thin strips of stock set on the edges of the member to ensure the jig is clamped square or parallel to the reference face. I think one should maintain as much contact as possible without scooping the housing. I just square the corners with a corner chisel. I fit things as they are when I'm cutting. Trying to second guess what the timber is going to do as it dries makes my head hurt. I draw bore to prevent any withdrawal. I also work on site a lot so I cut and assemble within days with minimal delay as possible. I think an assembled draw bored joint with each timber's forces working against eachother stands the best chance of staying tight. The worst part about using a router is all the sneezing! lol.

BTF, why maintain as much contact as possible?

I second TimBeal's question. Maintaining contact in certain locations is warranted for bearing or setting distances. But trying to mate 2 perfectly flat surfaces of a material known to move seems an impossible task.

It just seems to make sense to me. I cut out the housing and it is flat, as long as my cuts on the end of the housed timber are true, there is relatively full contact. I cut the mortise a little deeper than the tenon, but the bearing surface sets the length as well as provide bearing. The scooping doesn't seem to be necessary, and removing some of the bearing surface seems counter inuitive to me so I dont do it. I would to improve an ill fitting joint though. But usually, like I mentioned, I'm usually too busy sneezing after all that router work.

I don't remove bearing surface(s).