Right now I'm building a pair of the Sunn 2 x 15 cabs that came with the 67/68 Sunn Sentura II amp. The design is the same used for the Sunn 230-B-60 amp ( 36h x 24w x 11.75d) and with the offset 15" JBL's. [ Note: I'm using JBL K-130's instead of D-130's]. If you are interested, pleas let me know. When I'm finished with my cabs I'll try to estimate the cost of doing the 200S bass bottom. Do you want the speaker baffle grilled, or do you wish to do it yourself. You will have to tell me what type of grill cloth and vinyl covering you want. I'll tell you right now that the Sunn style vinyl is no longer available. I use a pebble grained vinyl, and a black/white/silver grill cloth that I get from Mojo Musical supply.
I used 17mm ( scant 3/4" ) 11 ply birch plywood with 3/4" x 1" custom cut clear pine rails for mounting the baffle and back. The cabinet is assembled with full corner cleats that are cross screwed and glued with high strength wood glue for strength. The mounting rails are also glued and screwed for strength. I use a 2" caster that is almost identical to the one's used by Sunn and are mounted with T-nuts and insert Nuts.
I believe that there is a drawing of the 200s cabinet on Sunn Shack I. The 200S cabinet was a front mounted bass reflex cabinet. I will also need to know the type of speaker that you intend to use and it's dimentions. Some 15" bass speakers are deeper that the D or K series JBL's. If you use anything other than a JBL D or K 140, the horn of the bass reflex may need to be altered to accomodate the magnet of the speaker.
Let me know if you're interested.
Robnatgeo at A O L dot C O M