debos,
Well, where to start? I only know about the union situations in Las Vegas and primarally the casino world so everything following is pertaining to shows and union situations in casinos. There are many wonderful smaller theatres around but not to many large shows happen in them. I also can't go into a lot of detail but i'll give you the gist of things and should be able to answer your question. I'm going to go into a little bit of history here. As far as speculation goes, Las Vegas was founded by the mafia. Just watch "Casino" sometime. Unions were also supposedly influenced by the mafia. So Las Vegas has become a town heavily influenced by the Unions. IATSE has a fairly large presence but does not have a monopoly on the stagehand gigs around town. I would say that IATSE accounts for about 30 percent of the stagehand and theatrical work done around town. As far as AEA goes, there is minimal presence. There are many properties who use independant or in house stagehands. I believe that the Blue Man Group is currently in litigation over them refusing to use union labor.
When working with IATSE there is extreemely low turn over when it comes to being a perminate employee on a specific property. Some places have the same crew doing the same show for over five years. However once you are part of the union you can always go out on the bounce and pick up random work almost daily. One recomendation that I can make is that if you do join IATSE take as many training classes through the union as possible. They only cost you your time and will allow you to work more gigs and possibly at a higher rate of pay. Basically when you first join you will be out on the bounce until a new show comes into town and the property steward decides to put you on it. Being on the bounce means that you are filling in positions here and there and doing a lot of load ins for conventions and touring shows. But you will be making fairly good money. The Local 720 allows its members to work outside of the union as well so you can always pick up other gigs on the side as long as you are paying your dues.
If you are just moving to town or just starting out I would recomend joining the union to get to know the ropes and get some credibility around town. You get into a great social network and start to find out about job openings here and there. After a while you may decide to leave the union or you might stay with them.
As far as stage manager positions go, they are almost impossible to get. The possition of SM is not a union possition and it really depends on the house and the produciton as to who's employee they are. Your best chance of getting a traditional SM position is to get on board with a produciton that is comming to Vegas and hasn't found a home yet. I get about five pitches a day so I know that they are out there. In that case you would be the SM for the production and paid by the producer. You would work with the venue's stage manager or entertainment director who would give direction to the stagehands and anything you needed done to the theatre. As far as Casino or venue SM's go, well there is extreemely low turn over and to tell you the truth I have no idea how to go about getting a job like that. It seems that this entire town is based on relationships so start at the bottom and pay your dues. Even if you have to do it all over again. But keep an eye out for job postings and something will pop up. I'll keep an eye out for positions and post them if they pop up but i havn't seen anyting in a while. I really don't know if I have answered your question but I made it look like I wrote a lot so hopefully people will think that there is alot of prudent information in the above paragraphs. And I know that I have been fairly vauge and topical so let me know what other information I can give you.
peace,
chops