I can't answer to all your questions (never had custom IEMs and problems with the 3003 in order to deal with AKG customer support), but I'll answer to the other ones.
They require an iOS device for the volume and if memory serves me well, I think I was able to control my "old" (2009) macbook pro with them at some point, not 100% sure about that, however, the new macbook pro retina does not respond to the remote controls. I'm pretty sure the android support is missing.
I used Comply tips with them, there's a compatible model.
As for big headphones resemblance in sound, I have the T1 and while the sound signatures are different, with the proper source (I use a Lavry DA-10, which makes the k3003 sound outstanding), the detail retrieval is on a par with those, though I always found the BA based IEMs to compress the sound a bit compared to dynamic based headphones (less depth). They also share some similarities with the HD-800 (both are bright phones with tons of details but also fatiguing to my ears if un-eq'd), but overall the HD-800 has the edge. Anyway, IMO the 3003 beat the HD 650 in almost any aspect I can think of.
Compared with other IEMs I'm familiar with, they sound somehow similar to the FIBASS, though have better bass due to the dynamic driver and an overall slightly more refined sound. Compared to the W4, for instance, they surpass them in every way, making them sound flat (like in no depth) and dull.
If you are sensitive to high frequencies don't buy them, or consider from the start including an eq in your chain. The Comply tips tame the highs, but not the low treble (around 5-6kHz), which, like those of the HD800, are the most offending ones. You'll also lose the sparkle, especially if you'll use them with a modest source. With the right eq and stock tips they do sound beautiful though.
Edited by tumburu - 2/17/13 at 4:42am