I would recommend holding out too for either RK2 or the Roadster.
If you have not taken the opportunity to actually play through any of them, look for the closest Mesa Dealer and plan a trip. For me that is a 3 to 4 hour drive one way depending on traffic. When I had interests in an RA100 I bid on one on Ebay, then realized what if I did not like it, so off to the closest Mesa Dealer and lucky they had two (head and combo). I was able to get the jist of it in the shop but hard to open it up to really hear it sing. I am very pleased with the RA100 but I bought it for a purpose, blues, jazz and classic rock and it does a perfect job. It will sort of get to Metal tones but it is not a Dual Rec or Mark V. I bought the Mark V over the Roadster in November of 2012. The V was a bit more familiar to me that the Roadster. Had I changed any of the settings on the back panel of the Roadster that may have changed. I was after something different than another Mark amp since I already had the IV. The V basically sold itself. However I was still missing that specific tone that is legendary of the DR, TR, and it is in there in the Roadster too.
The Mark V has two distinct tones to it. CH1 and CH3 are traditional Mesa quality tone and character that is similar to both RA100 and the Roadster as well as the Mark IV. However, there is CH2 which has a Mark I overtone that seems to govern the character of that channel. Super sweet and sinister low mid enhancements. There is a similar character to CH4 of the Roadster that is reminiscent of the Mark I but not quite the same range of mid enhancements. As for the RA100, the clean channel is all that is needed for blues, jazz, up to classic rock and is similar to CH2 of the Roadster. The Hi/lo channel (RA100) is more like Vintage and Raw voice of CH3 on the Roadster. The Lo setting on the Hi/Lo (RA100) is also similar to the Edge voice of CH2 (Mark V) Keep in mind that the RA100 had far more headroom than the Roadster so gain structure will be quite different. The range of gain as well as trimming the character with the Presence control makes the Roadster quite versatile. If I had to choose to keep just one, that would be difficult. I would probably keep the Mark V but yet regret loosing the other two.