What exactly do you mean by a walk in shower? A typical tiled walk in shower will still have a curb. Even doorless showers usually have curbs. That said, for looks I would definitely go with the tiled shower over a pre-fab anything.

Jason has a curbless prefab shower unit that looks like it was meant to fit in tub alcoves and work with folks who need wheelchair access. That is a flush drain line across the front. I think you could tie it in with a wainscot and/or tile treatment and have it look very nice.

Here is a link that might be useful:

This is what we're hoping to do. It *looks* like it doesn't have a curb. Or maybe it does? The gal at our local flooring/tile company says that it's doable because of the size - a smaller area would need a curb.I don't know..this thing doesn't need to be wheelchair accessible. But I really do like the look of a tiled shower rather than a prefab stall. If it won't be cost prohibitive? The other thing - we're doing a bear theme in this bathroom (we've got bears on our property) and found some *great* bear tiles that we can use as accents in the shower. If we tile it, that is.

Here is a link that might be useful: Walk in shower from Houzz

You can see how we're doing our corner shower. We're doing the tile work ourselves. I asked my friend who's helping and he though it would be around $6,000 if we paid someone else to do the tiling. Ours is 4'X4' and we had to raise it to fit the plumbing in. I do love the love of the tile as I put it in.

Fun with tile. I'd think a tile setter could do the shower if you went that route. Doing it myself I do walk with longing past the put in place showers. It's slow going doing it ourselves.