No built in speakers on any KB are loud enough to cut through and match the output level of drums, bass and guitar amps. Not a very practical approach. Moving digital pianos that require wooden stands and have a fully weighted 88-note keyboard isn't really impossible but can hurt one's back. Wooden stand is about all I would use with those since light metal stands can do the job but to my experience they aren't as solid and are generally made for KBs with 64 or 76-note with light or semi-weighted action. Again, this is according to my experience.

I just don't like the stand moving around or sort of shaking under the keyboard when I get into some loud and intense playing.

Just curious, why don't you put the money towards something used with decent enough sounds, add a pair of external speakers (self powered if you wish) and play like most professional KB players do? Why the search for all the odd stuff?

Sure, there is always a bit of risk buying used gear but it's not like it's the end of the world.

-ED-