Safest bet would be RB4011 (with our without wireless), it comes with rack-mount “ears” (or, if not included, it should be possible to get some). However, it seems to be pretty picky about SFP modules used …
And selection really depends on what is reference price point when looking for “cheaper” device.
With these requirements, I’d say the RB4011, with or without wireless. You didn’t say how the connection would get to the router: is it fiber? Or do You have a media converter?