Storing a 5 gallon beer at room temperature

I reckon it depends on the beer

 

Home brew or commercial and what style/brand?

 

I routinely store most of my homebrews at ambient cellar temperature (in my house, that's 58 to 60°F year round... that's also the serving temperature).
It poses no problems.

My annual Solera Holiday/WInter Ale (which this year is in it's 27th year) spends an average of 8-9 months, racked into a carboy at that same temperature, before transfer to a keg in late November for carbonation..

As long as you've kept your fermentation ,racking, and all related equipment properly clean (and your transfers are as O2 free as possible), there is no reason to worry about keeping your kegs at room temperature (and it actually improves the beer) .
If you are concerned about hop aroma (which certainly fades over time), you can dry hop the brew a week or so ahead of serving/bottling time.

 

Unfiltered homebrew will keep for a good while. Basically there is little chance it will spoil, that is to say the bad bugs which are present (they are) are not likely to take over. This is not true for unpasteurized or fine filtered beer (domestic keg beer should be kept cold, with very little exception).

The rule is that alcohol and IBUs are preservatives, so the more of either the better the beer keeps. This is true of all beers regardless of where they originated.

I wouldn't go as far as @LukusDelph and suggest warm storage improves homebrew, or any beer for that matter. It may. It may not. It will accelerate everything though and that includes staling and change of flavors, hop aroma in particular. So an RIS could change for the better but a light lager certainly would not. And better is subjective anyway. Different might be more appropriate.

Be aware that your carbonation will probably be off, and don't vent the keg unless you want to lose aroma. When ready to serve let it sit at serving temp for a while to help clear the beer and to get the carbonation in check.
Cheers.

 

I had a 5.5%abv home-brew sit at room temp for a month and it was fine.