Well, need some more details...like your batch sizes, your equipment, size of your intended kegerator, etc.
The answer can certainly be yes. If your kegerator will hold two cornies, you could lager in one corny while dispensing from another. If your kegerator only holds one corny, then you won't be able to dispense and lager at the same time. With lagering times of 4+ weeks, that's a long time to go without beer on tap.
Or you could use a full sized fridge. Lots of options here with the added space. It's pretty much up to your budget, your available space, your creativity, and approval from SWMBO.
One key piece of equipment here is temperature controller. It's nice to have predictable and consistent temps for lagering.
Edit: by 'lagering' I'm talking strictly about the aging portion at colder temperatures (not the fermentation of a lager beer). For this scenario, yes you can still do it but I wouldn't try to serve and dispense at the same time. 48-50F is a little warm for serving IMO.