Hi! Our high school recently got a new marimba and a new vibraphone. But there's one problem. These instrument's frames don't match our old ones. We already have 4 marimbas with the RD-2400 frames that comes with Acoustylon marimbas.
The original ones we have (RD-2400) (Picture provided below.)
RD-2400

The "new" ones (T-2400) (Picture provided)
T-2400

I'm just wondering where I can BUY either used or new RD-2400 frames. I've found A LOT of places that sell the T-2400 frames but so far I've found none that sells the RD-2400.

If anyone could tell me where I can buy one for a reasonable price please comment! Thanks!!!

Why are you worried about them matching? Is it just an aesthetic thing? If you're doing your jobs right, the audience will care a whole lot more about what's going on ABOVE the bars than what's below them.

Both frames are functional, but the T-2400 is actually a heavier-duty frame. In my opinion, it would be a waste of time, money, and effort to replace them.

Well for some reason the "new" one that we got sounds A LOT worse than all of our other ones. The keys, however, look like they are in wonderful condition. So we decided to place the "new" keys and resonators into one of our old frames and it sounded better.

I don't know if all the T-2400 are like this or if it's just the one we bought.

Also, it is a PAIN to move the T-2400 frame. AND we want our marimba line to look more uniformed.

If it's simply a uniform look you want, could you position the one frame that's different in the center of the pit, so everything is matched on either side of it? Coming from a line that had a lot of mis-matched equipment, we always arranged it to be visually appealing to a degree, but never stressed about making sure everything was exactly the same; often we used the idea I suggested, use a "pattern" or other arrangement to make it uniform and the same, though not all the equipment may be the same.

Also, if the "new" keys sound better in an old frame, would just swapping them out and using a new frame with old keys and new keys with old frame solve your problem?