IMHO, I would love to see Mesa make an exact reissue of the reissue, but I can see pros and cons to it.
First the pros. Mesa knows it would sells tons of a C+ reissue. That's why they attempted to get so close to it on the Mark IV (they duplicated the Mark IIC Lead curcuit), and they added a C+ mode on the Mark V. Also, if they worked with some of the original suppliers to make exact replicas of the transformers, Caps, ect., it would definitely give the parts suppliers a decent bump in product sales. So, overall, guitarists win with an exact reissue, Mesa wins since they sell a ton of units (provided the price point is fair), suppliers win with increased demand. Sounds like a good deal, right?
The cons. If Mesa did an exact reissue of the C+, which would they choose? The have long heads, short heads, simulclass, export Trannys, ect. Quite a few options to choose from. Now, if memory serves me correctly, they based the C+ mode in the Mark V off Doug West's non-GEQ C+ because they favored its tone over the other C+s, and the non-GEQs have different caps on the tone circuit. In short, purists will always say the originals always sound better, even if the reissue 100% correct, but it most likely never would be. Some of the original suppliers are no longer in business, therefore, you could have another company make an exact duplicate of say the original STRs for example, but I have a suspicion that no matter if it's a perfect match, there would always be some skepticism that brings attention back to the original C+s on the used market.
Also consider Mesa's business model of "always moving forward" (not necessarily always improving). The reason why there are few C+s in the first place was because Randall saw the Mark III as superior to the C+ and rushed it out as soon as he could. I love my Mark IIIs, but it seems unanimous that the feel of the C+ is somehow missing, even though, at least in theory, a 3 channel amp with the C+ design would seem like a huge improvement. Even though Mesa knew they had something special with the C+, they wanted to make it better. I think you can see their efforts to move forward with the C+ as the definitive "Mark tone" since the revisions on the Mark III feature a preamp and power amp attempt to go back to the C+ in the Red and Blue Stripes. I just don't see Randall doing a reissue because the guy always wants better, and I can appreciate this mindset with Mesa. I think all Marks going will always be (at least in theory) a step closer at getting the C+ feel back into a Mark, but it will need to be an advancement in the amp itself.
With the inavailability of certain components, I highly doubt Mesa could keep a decent price point to accurately reissue a true C+. Parts aren't available anymore, and they were critical to retain the feel of the C+, and while it's possible to reverse engineer any of the components, what would they cost? I think a true reissue would make the going rates for C+ on the used market look like a bargain.
So, while I would love to own a C+, unless I can find one on the used market at the current price point, I think we could only look to Mesa to release a Mark VI, Mark VII, ect., that finally nails the feel of a real Mark IIC+. A reissue would be priced too high, and Mesa wouldn't take a step back just to "risk" naysayers making claims that the reissue is off by .001%, so it's inferior to the original.
Just my long winded .02, but the topic seems to come up ever couple of months, so it seemed like a good time to chime in...