MT has the OTC Elk tags. The good thing about MT is with a General Elk tag, you have the whole state to hunt elk, excluding a few "Trophy" districts. You will definitely want to read the regs closely. The bad thing about MT is there is a ton of private land. During archery season, you can still find elk on the public land. From what I have seen/heard this season, the elk is SW MT pretty much bail to private as soon as the rifle season starts and finding them on public land takes allot of time and patience.
MT does have a very useful tool to research though. It's called the hunt planner. It's a map that shows all the different types of land (private, NF, BLM etc) It will also give you statistics for units but keep in mind they are not always the most accurate because allot of the "High success" hunt districts show a high success because of FWP check stations. Heres a link:
http://fwp.mt.gov/hunting/planahunt/
If you have the time/money and want a big trophy elk, Arizona has some of if not the best elk in the country. The tags there are draw only and drawing an archery bull tag is like winning the lottery, but well worth it. If you spend the time scouting and know what you are doing, a 350 bull is an easy find and kill. Depending on the unit, a 400+ bull is not out of the question.