Built a non reverb DC30 some years back. For that purpose I would prefer to (and did) use the 30 watt set Dave West has (Westlabs.com). If you want to get other trannys I'd suggest a little overkill.
Maybe a PT with secondaries at 265-0-265 vac at 350 ma, 5v at 4 amp (for the single/double rectifier option) and 6.3v at around 6 Amps. I like my PTs flux banded FWIW.
The OT probably should be something along the lines of a 40-50 watt/4K pri-Z OT with multiple taps (4&8 or 8&16 should get it but all three would be nice). I'm certainly no expert but I like my OTs interleaved & laminations (EI is OK with me) made from M6 oriented steel. Dave Allen (Allen amps) has some really nice pieces along these lines.
Built my own head & cab & I don't know anyone, other than perhaps mojotone, who does or would do a one-off of a matchless cab. Even still you'd have difficulty finding a chassis to fit.
It is a great circuit! As an alternative you could build it as a head only. That way you could use something like a Weber 6A80 chassis (with some minor modification) & I'm sure you could find a head cabinet to fit that. You could make your own faceplate design in Corel Draw & have it laser cut at BNP lasers (Jeanne Kangas).
The reason I suggest that chassis is, although I've not used it, that it looks as if you could shoehorn in the trannys with room to spare and still leave you with 2 octal & (using adapter plates) 8 nine pin sockets.