Hi Dimitar,
First-off let me say that your responses on this website are extremely helpful!! Thanks!

I am a dentist currently working on a H1B visa (5 yrs remaining). I now have an offer to start a new practice with me as a 50% partner along with a US citizen as the other partner. I plan to work part-time for this new practice and continue to work part-time for my current employer. Questions:
1) Can that new firm sponsor a concurrent H1B visa for me?
2) Can the new firm sponson a Green Card for me and my family?
3) In a scenario where my spouse (also on H-1B visa) becomes a 50% owner of the new firm instead of me, can that firm sponsor my concurrent H-1B visa and/or Green card?

MANY Thanks for your insightful answers.