I kegged a pinot blanc for my wedding party about 8 years ago. It was forced carbonated, somewhere between 20-30psi and served cold at a low psi. It worked out well. I forgot about it in the back of a fridge (34F) and tasted it recently. It held up really well, even improving over the 8 years. Both then and now, the head didn't hold very long, but you can say that for most sparkling wines. The size of the bubbles got smaller over time. You could try the Charmat process, which involves adding some reserved sweet juice to the fermented wine in the keg to carbonate. It should give you a quality somewhere between Méthode Champenoise and forced carbonation.