yes and no, rather it depends most maya controls don't have mouse over events however most can support a popupmenu trigger. Now tis is potentially damaging to mayas health so while you query this remember it does change maya slightly. Idea is to roll trough all already created controls (not ones that will be created in future) in maya and add a pop up on every item.
Heres a piece of mel that binds shift+ctrl+rmb (its least likely to clash!) to a pop up that queries name, select the item to see full name. (im doing a bit of shorthand here so you may need to execute it 2 times so it runs it, is hould cast i to string)
CODE
for ($i in lsUI -l -controls){
popupMenu -sh 1 -ctl 1 -b 3 -p $i;
menuItem -l (match("[^|]*$",$i)) -c ( "promptDialog -message \"Control name:\" -button \"Cancel\""+
"-defaultButton \"Cancel\" -cancelButton \"Cancel\" -dismissString \"Cancel\" -tx "+
$i);
}
If you wish to make it proper you may need a few ladder overrides for tool buttons etc but...