Is there any project of abstractions that uses Gem as Graphic User Interface seriously?

I mean: Create other design of tables, envelopes, data representation, even other design of buttons, leds, sliders and knobs that could be manipulated in realtime....

A library of Gem objects for that could worth? Or it would be too much cpu expensive for DSP audio ?

I'm curious about it...

Do we have some examples?

thanx

glerm