Whoeversaid you cant have any shape as button in maya! becauyse as a matter of fact you CAN. however having html page for this is perfectly valid in my mind, a bvit over the top... but yes you can do prettymuch the same in maya! Ok so the regions are limitted into squares but nothing states THEY CANT be one cotinious image. imean alot of webpages do this succesfully. And mind you when you do it right no one notices.
Anyway the dowside of html is that you now cant have a fully dynamic gui, easily anyway. however if ist somesort of oneway static compiled button its fine (its not like you cant regenerate the HTML buttheres a quite limitted communiacation flow so you cant change them runtime, wouldnt it be nice that your gui rflected what selected for example).
THis is however possily sortof doable with setFocus, but its a MAJOR hack
but flash ist like saying hey we are plonkers. Anyway modify teh marking menus isnetad and put teh gui ON your screen and disable all extra panels
thats what i do works like a treat one can have all you need on rightclick.
BTW maya can even do highlights on those buttons whan you hover over them no problemo.