Can one listen to Rush Limbaugh anywhere on Sirius/XM?
According to several links on teh Googles, Rush is not on satellite radio. There is also no indication on his website that he is.
I wouldn’t expect him to want to go there. His current business model of syndicated talk radio is still extremely profitable. For one thing his fan base skews older so they have no problem listening to him on terrestrial radio (even AM!) You can also subscribe (and pay) online and download any of his shows with the commercials edited out (like a podcast).
The key issue that made Howard (Stern) want to move there was not having to worry about FCC fines. Rush doesn’t have a lot of retarded strippers on (insert your own political joke here…) 
Limbaugh is not on Satellite radio. I’ve heard that he is very loyal to AM radio since they gave him a chance in his early days. My understanding is that he has no interest in moving to FM or to satellite radio.
I believe he was on a few FM stations years ago and also short wave.
I’m thinking a proportion use crystals, cat’s whiskers and earpieces whilst stroking their rifles and swigging bourbon.
WRNO shortwave carried his show. I think in the local market he’s actually on FM. But it still looks like the answer to the OP is ‘No.’
There is a conservative talk station but no Rush. Hannity, Beck and Mark Levin are on it though.
SiriusXM does carry shows that are also syndicated elsewhere. It is not all exclusive programming. Particularly on their political channels.
Plus on the flip side, because it’s close to physically impossible to be somewhere in the US that’s not in range of a terrestrial station that carries Rush, carrying him wouldn’t really be much of a perk for SiriusXM subscribers. That’s part of why the left wing talk station has always been a lot stronger there, since there definitely is the market for that but unlike the right wing stuff it’s not served by terrestrial radio in most places. (Plus they were able to scoop up most of the important pieces after Air America imploded.)
The existence of FM and satellite radio is too “progressive”, shall we say, and not a part of God’s natural order. Besides that, dinosaurs listened to AM radio. It’s in the Bible.