Hello Alex,
this is a nice 'Googled' concept taking into consideration the incredible growth of home-made short videos, teasers, clips, jingles & so on... you could offer them a great visibility and you would make the best use of this great source of free stuff. One could think that you even ask your visitors to vote for the best videos by categories, winners could get prizes from affiliated sponsors. Many options could be added to a such site. Video compression/conversions should not be a problem at such as long as you have set your broadcast format(s) and that participants send you their videos according to your technical requirements, minimum maximum durations & so on... (do not forget as well free free licensing rights and make sure that videos do not contain copyrighted materials !) Another main concern is, as you know, running videos required specific streaming server(s) otherwise your traffic audience will not last long, and depending the size of your site, number of videos available, your line(s), .... the inve$tment can be heavy.
Another concept which I feel more intuitive as per your name is to develop a reference portal about major theatre and broadway scenes, concerts, spectacles.... A few info lines per category event with links forwarding your visitors to organizer/agent sites, would be just perfect as a start. One could think that you focus at first on a selection of capitals where major 'on stage' artistic events are used to take place, then step by step expand as per your traffic, demand, and thanks to your growing network of contacts interested in the promotion of (their) spectacles. Animations of stills,affiches, short video/audio excerpts would attractively supplement this 'On stage' promo tool.
Easy saying but your name is worth a brainstorming.
Good luck with 'OnStage.tv' !
