SONIC. said:
Tune that's pretty damn cool.
ADV those speakers look great!
For MDF try Bondo, I've had really good luck with it.
You can put an ultra thin layer over the outsides too and sand it back to flush to get a paint ready surface.
I bought a pair of rectilinear highboys a few months ago (fuckin awesome speaker). They sounded completely different than my center channel though so it made movies with surround odd to watch. So I decided to buld a center to match.
Scored some 1967 Phillips mids from eBay and built an elcosure for them from leftover cabinet ply with a walnut box. Put some Dayton drivers crossed around 400hz for the low end and a Dayton tweet at 3000 for the highs. The thing sounds amazing.
Im still waiting on the speaker fabric to come in to match the rectilinears.