I'm probably going to still go for it, DIY plans for the bass bin are available and the K-402, drivers and crossover schematics are all still out there and available.
Looks like a tough build though, I've never built anything more than boxes.
I don't know if the quote is up to date, It was $10,295 for two of the KPT-JUBILEE/535-B two half years ago from American Cinema.
This was when I bought my pair of KPT-904-Ms.
Ok good.
I finally have a space big enough and I was saving up the $10k I'll need but there's no chance I could ever save $35k, that's just out of reach.
It would be cool to build a pair that adds enough height to be front ported, it would make these speakers a lot easier to place. My KLF20s and KLF30s always wanted to be closer to the wall than their rear ports would allow.
I'm looking forward to seeing the finished results and possibly the measurements from the OP. I've always liked the looks of the KLF towers and I think developing an upgraded version is a worthwhile project.
I got rid of them because I heard a pair of KI-396 and was really impressed, even though they lacked a little on the low end compared to the Cornscalas. I eventually replaced the KI-396s with KPT-904s.
You're making too big of deal out of this, I no longer have my Cornscalas, but resonance issues were easily fixed with 4 lengths of 1 3/8" dowel rod to better couple the front and rear panel together. I used glue and clamps to attach them to the front panel and flush mounted bolts to attach to the rear.
Cabinet resonance issues aside (which can be fixed pretty easily), the two-way speaker will work a lot better in a smaller listening space. If you have 10'-12' or more between you and your speakers either should perform well for you.