Yep, I would leave the D5000s out of the equation. Look to play around with what you already have through mods or go with the D7000. I really liked the D5000s but found the bass too boomy and essentially a liability that made me pick and choose which tracks would be more well-suited. I can definitely see a mod for those and perhaps I should have at the time, but I just liked my GS1000s better and sold off the D5000s.
The D7000s on the other hand are more suited to my preferences than any other headphones I have tried and from a technical standpoint I think they are up there with or surpass the biggies that I have owned (GS1000, K1000, L3000, W5000, W11JPN, HD650, HP1000, RS1) or auditioned extensively (Stax OII, DX1000, and quite a few others) Since getting them, I have felt completely comfortable selling off all the rest of my headphones in part because I feel they handle all genres very well and excel at the ones that I listen to most. They will not suit everyone as well as me, but there are lots of extremely pleased owners out there. If you like the stock D2000s so much, I suspect you will really love the D7000s.
I had a pair of recabled MD2000s side-by-side with the D7000s for a few weeks and preferred the D7000s sound signature and felt they had a technical leg up as well. I am sure some will prefer the MD2000s, and the investment of time and energy into a DIY and the money savings will contribute to an extra sense of enjoyment. You could cetainly give the mods a shot and see about the results. If you do it right and do not strip a screw or something, then you will increase their resale value a bit. You might be really happy with the results.
I do have a couple of issues with the mods though. One biggie is the warranty. The D2000s/D5000s have a history with troubles with the little bolts. I think this was addressed in the D7000s. The D7000s have a warranty, all modded versions do not.
Also, in terms of 'face validity', I feel more comfortable with knowing that changes are being made at the driver level rather than by jamming bunch of damping material into the insides of the cups altering the what was designed and tested by the developers. Even beyond that though, the improvement was slight (everything is at this level) but noticeable, and I felt the D7000s were more focused, clearer, and more detailed, and the bass had better decay and bloom and sounded a more natural.
If you are keen on the D7000s, keep an eye out in the FS forum as they do appear and Headroom occasionally has B-stock as well. They have a pair currently for $629.
Regardless, it is great you found headphones that you like so much in the D2000s and yet you still have options for taking that sound signature to a higher level!
