Like you mentioned - ProBalls only come in one size (as far as I'm aware) which are quite tiny for CJ.
For glow-in-the-dark stuff I use a Mathmos bubble ball (www.mathmos.com) which looks nice-ish from a distance apart from the large plug socket, but even GloBalls have these. They don't change colour or anything (it's either on or off) but they're not a bad size and quite a nice feel to them (which is apparently meant to resemble skin...)
If I'm under UV I just use a 4" Dubé luminoue stage ball from
www.oddballs.co.uk which cost £4-ish and look pretty nice. It's the kind of "charge up under a light then it glows for a bit after" ball but it goes reall bright under UV.
I've never seen anyone using a colour changing ball, but I'm sure they exist somewhere. Toy shops are great for finding CJ props.