Sadly, I haven't yet
I'm shocked that patching subs into a BDMV is somewhat simpler than a VIDEO_TS folder - not faster, not by a long shot, but you can do the whole thing with just a few programs and the results do seem to be BD specworthy. The only real problem is that the subtitle possibilities using TSMuxeR are very limited - it uses SRT scripts, not anything fancy, so if you want to put a subtitle at the top of screen or use multiple colors or whatever, that just isn't going to work. Now, as I understand it you CAN make very flexible BD subtitles using freeware, but that requires pro-grade authoring tools as well, which a few thousand dollars out of my current price range.
The bigger question is what this means for the future of the Kentai Films online catalog - would Blu-ray titles sell, or is the market for bootleged anime and cult films naturally too cheap to support it? Would consumers rather pay $25 for a recompressed single layer disc, or $35 for a complete dual-layer? If there were no menus on some experimental titles, would that be a deal breaker? This is a very exciting, but also very difficult chapter we've entered here... all I can say for sure is I'll be experimenting like crazy, trying to figure out what the best compromise for everyone involved might be.
Sorry for the lack of updates on both the site and the blog. Been pretty sick and had my hands full with all sorts of car trouble.