If you plan on working with stress skin panels a Prazi should prove useful. I bought one to cut scarfs and SIPs but have only used it for end of tennon cuts on big posts.

I've more recently purchased a Logosol Timberjig to deal with oversized logs. I find I can rip timbers to the line on the visible side and tweak the bar so I'm predictably ~1/16th above it on the far side. The cut is very smooth for a device designed to produce rough sawn lumber and timbers, cleanup with a hand plane is very quick.

If you have a good strong chainsaw then the price is going to be about the same as a Prazi.