It's more of chips in general, because chips used at table games are the same as the ones used in the poker room at that casino...
In regards to taking chips from one casino to use at another, it can't be done...not only would this create an accounting nightmare, but I think it's also against the law...but don't quote me on that.
As far as table limits, they are always going to be in relation to the minimum bet size. For instance, a $5 table will normally have a 'spread' of $5 to $500, a $25 table is usually $25 - $1,000 or $2,000, and I've seen $100 tables with a limit of $6,000. The bottom line is, if you're betting the table max already at one of the above tables that I mentioned, and want to bet more than that, then they would expect you to move to a table with a higher limit...
9 times out of 10, if you want the limits increased, you simply have to ask the pit boss, and if you've got enough cash/chips/credit, they will raise the limits for you without any problems.
But, don't ask for the limits to be increased unless you're already playing $5,000+ a hand. They might look at you funny...
edit: Don't quote me on this, either, because I've never ran into this situation; but I don't think they can raise the table limits unless you're in the high limit area, and not on the casino floor....I guess it depends on the casino and how many players are at the table, etc..