Best poker rooms Downtown Vegas

Do any rooms around vegas have 1-2 or 1-3 nl with a max buy in of around $400? 

Not that I'm aware of. $300 seems to be pretty standard. 

$300 sounds good. Where would I go for that? I want a buy-in limit. I don't want to be in a situation where I buy in for $300 and someone else buys in for $5K or something crazy. 

That's pretty much standard everywhere. I think Caesars lets you buy in for $500. 

In any event, since you're going to be playing table stakes, it doesn't really matter if a player has much more on the table than you do. If you have $300, and he has $173,540,222, when he's playing against you, he has ..$300.

Of course, a large buyin cap could affect the character of the game, but I love that. If I'm the short stack, I know I'll get action on my good hands. And my opponents won't get the proper implied odds.

Excellent point. 

This is true, but from my experience starting with a smaller stack than the big guns at the table who have 10k plus, they will bump their raises and re-raises at 1-2/1-3 to $12-20 and sometimes more to make the game play larger as well as put on a straddle.  So the table plays much bigger, your range of cards you'll play is much smaller (and they know it) and you have very little fold equity when you jam.  I found it profitable for my type of play, but it is a much different game than everyone sitting with under 5-600.

I mentioned that, but the flip side is that calling you when you raise preflop isn't as profitable for them since you don't have enough chips to give ththey em good implied odds. Of course, you can't make speculative calls of their raises for the same reason. 

I like it that way because they rarely have the discipline to fold.