I have a maid's bath too so I know about the floor space. The biggest concern about keeping the floor clean should be about the grout--the more grout the harder it will be to clean. So, go with the biggest format tile you can to reduce the grout lines. I bet that you can get away with 12 x 12 without too many cuts if you lay them straight. You could also consider a wood floor.

What are you doing with the tub? Are you keeping it or replacing with a small shower? We got rid of the tub and just have a half bath now with a great sink and countertop. It is all open underneath so you can really see the floor tile. If losing the tub is an option for you, it might be a good one. If you need to keep as a full bath, a stall shower might be a good idea.

Large ceramic tile in a small room will only make it look that much smaller. Grout should not be an issue if installed correctly. If doing ceramic tile, I'd go with no larger than 6x6 tiles on floor.

I also think hardwood would be dicey in a bathroom (water, urine splash around toilet).

Why not do some kind of vinyl / laminate tile? It's cheap, durable and easy to install.

I would do small white hex tile or white-grey text tile with a grey grout. Large light colored tiles will show every hair and piece of lint, especially if you have pets. The grey grout in my parent's house, while maintained, has never been cleaned with grout cleaner or redone in any way in 40+ years. Contrast this with a client who insisted on white grout and it got stained before construction was done.

If you want a really modern look and the subfloor is concrete as in a highrise you could just epoxy the floor.

I like jillalameda's idea. I have seen slab granite flooring & baseboard. Depending on the measurements, the job could be done from a remnant. If the floor joists could take the weight, I would have done this in our house; the look is extraordinary. The ones I have seen are very elegant, very expensive looking and really gorgeous. I'd check local fabricators in your area for scrap pieces of granite or marble.

Thanks for the suggestions. This is really tiny and unfortunately can not replace half-bath with shower (what I wanted to do) since then would have to bring the bathroom up-to-code and couldn't fit even a toilet in it. I think the idea of using white-grey tile with grey grout would work best. Can't use large size tiles since there is no space. But I can't find "text tile" in google.

Thanks

Nemo Tile has it.
(JMHO, but I would do hex or penny tile instead. Text always looks institutional to me.)

Here is a link that might be useful: Text Tile

Although, now that I look at it again, I think the all white with black grout could be sharp....

You could also get one of those Japanese style recycling toilets with the sink built into the top. Practical, and modern to boot.

You really need a sink for sanitary reasons after using the toilet. Have you seen these toilet and sink combos? Here's a link to a search showing many of them. I would have a shower instead of a half bath.

Here is a link that might be useful: toilet & sink combo

Blondelle--in NYC, many maid's room baths don't have a sink because the sink is located in the maid's room itself right outside the bath. NYChelen didn't say whether that is her setup, but I suspect it may be.

NYChelen--do you find the small tub to be useful? If not, you could turn the bath into a half bath and have a nice vanity and toilet. Would that work for you? I can't imagine that your co-op board would have a problem with that (if you are in a coop). I am president of my board and I know that we wouldn't have an issue.