The nicest solution would be to install radiant heating in the floor. If you are tearing up the present floor you may consider this option. It may exceed your budget.

The other option is to install a nicer looking radiator either on the wall or as a baseboard. Below is a link to a company that makes several types of radiators some of which can be custom ordered. You could even order one as a towel warmer and have it serve two purposes.

Here is a link that might be useful: Runtal Radiators

Radiant in the floor would be my choice too. A toe-kick heater might be a good option if you have a vanity rather than a pedestal or wall-hung sink. They go underneath and blow out warm air. A hydronic towel bar heater is a thought, but heat near the floor always works best if you want your toes warm.