My leather MotoLita steering wheel is dull and gets slimy if wet. Is there some product that would make it look nice and seal it from moisture?

I'd start with the Yellow Pages by looking up places or companies that sell Horse Tack & Saddle equipment & supplies.

There ought to be a ton of them where you live.

See what they suggest and what products they use.

Slimy when wet is not a good condition for a horse rider when out in the rain.

Tim - On the way to the Bonneville Salt Flats to watch the Healey Speed Runs.

a top for the car?

Eric Hi,
I have a Miata that I've been using as a daily driver for 6 years. It has a great Nardi leather steering wheel. After the first year, from the 10 o'clock position to the 2 o'clock position it became very dull and oddly 'dry' feeling, and felt 'slimy when moist or wet. I didnt like that at all! Whats worse, every couple of days it seemed to be spreading. I thought some mid summer hand sweat enzymes (?)had begun dissolving the leather surface.
I went to the local auto parts store and picked up a bottle of Meguiars One Step Leather Care ("Cleans and conditions all leathers in one easy step".
Before I had finished with the cloth wipe off, it had returned to its original luster, smoothness, and feel. Now at the first sign of a similar leather surface breakdown (about once every 2 years), I repeat the 2 minute process.

Eric, I don't think you ever should "seal" leather. being a natural hide material, it needs to breathe. I would clean it occasionally with saddle soap and then apply one of the leather dressing materials. Also, avoid products that contain silicones. They tend to make surfaces slippery, not something that desirable for a steering wheel.