Longtrack 2 is dead. Get it here. Take a look at its thread. It’s hopeless. 
That’s a shame, I’d be up for contributing to something like this but it sounds like it’s turned into a bit of a mess. I think it would helpful to make the whole thing cohesive and sound good if you specified some specific guidelines or parameters, such as BPM and / or key signature / root note to ensure the individual ‘bits’ work well together and can easily be pasted together or cross faded without inducing a brain haemorrhage.
For example if you specified each part must be at 95 bpm (or mutliples of) then in theory it should be easy and listenable to transition from a down-tempo / hip-hop part in E minor to a 190 bpm drum and bass part in G major. Doesn’t have to be those though…
Just an idea…
key changes and tempo changes aren’t a bad thing… makes for a far more interesing result imo. the hard part is to write good transitions. that’s one of the most interesting features of a mix imo. weird and daring transitions makes the whole more than its parts added up.
overly “key centric” music can gtfo too in my book (=