If you plan it right there should'nt be a problem. Also bear in mind that you will going to need some sort of an overflow to transfer the water from the main tank to your sump.
The biggest size of a sump you can afford the better. I mean the biggest you can fit inside your cabinet. You must also consider your existing equipment and stuff that youre going to need inside your cabinet. Also you need to plan for what other equipment you are planning to buy in the future.
Maybe a 20g is the bare minimum you can have. But I suggest at least 30 to 40g. I have a 10g for a sump but it is not big enough to kill the micro bubbles.