Those look really nice (doubt the Mrs. would allow them though.)
I just wanted to throw out there, that some print shops offer a metallic paper. It looks a lot like regular glossy, but has a very special reflective property that can really make pictures POP when the light hits them just right. These might look really good printed on metallic paper.
Also, you can get prints bonded to different types of backer boards with a protective UV coating (masonite, styrene, etc.) if you want to go for a more commercial look and don't want to put them in frames.
You could even do something called a floatwrap which allows the image to look like it is floating off the wall. It is new and I haven't printed a picture with this type of finishing myself, but it looks pretty interesting. (You can see examples of it in the picture below.)
I personally print all my stuff at www.WHCC.com
although it is more geared for working photographers as they require you to setup an account with a credit card, etc. They don't have any minimum monthly or annual quantities, there only requirements are a minimum of $14 per order.
Another place that offers more commercial services would be www.mpix.com
I have never used them, but a lot of photographers are happy with their capabilities.
I don't know if these guys would refuse to print them or not. They are pro print houses and they just expect that you hold the copyright, or proper release from the copyright holder, for any print you submit to them. You may find printing to any print house other than the minimum wage workers at Target and Costco to refuse to run them. Even if these are made from scratch and not physically copied from some other sign, it is still technically copyright infringement and a lot of places have provisions to deny illegal copying.
Walmart is actually one of the few mass-market print places that put some effort into copyright protection (although it varies widely by store.) Some in-store print kiosks will refuse to print prints that look professionally done. Although they have a standard copyright release form that you can fill out. Most photographers have commented that you are better off bringing in a completed release form before you submit the prints than you are of asking them for one to fill out after they deny you your prints (the thought is that you look a lot more professional going into the store with a release than you do asking for it after the fact.)
Anyway, just throwing that all out there.