NOS or barely worn would be my recommendation - the great names of the past are a shadow of their former selves nowadays. Leer and McDerm have both come up with some top NOS loafer finds recently (see elsewhere on the forum) so they are out there. Unless you have the funds for the higher grade loafers: Rancourts, Alden or Crockett and Jones. I don't own any of those, but I'm tempted as I always feel like I'm wearing cheap quality shoes whenever I wear my vintage Weejuns or Florsheims. (The only loafers I own.)

E'bay or Etsy for vintage NOS ( or even lightly worn) is probably your best bet to get some 'Made in USA' loafers,
Dexter, Bass, Sebago, Johnston and Murphy, JL Coombs are worth searching out.

If you want new at the lower end of the price scale try the big US department stores websites,
plenty of regular offers/discounts and can give you more options (in style and size/width) and often  work out cheaper than buying in europe ( my last pair FLorsheim Berkleys were under £85 including import charges from Macy's in their Xmas sale)

Agree with the above views, NOS US made is the way to go - but also think about UK makers if you have a little extra to spend.

C&J

http://www.crockettandjones.com/product/boston-darkbrown-grain

http://www.crockettandjones.com/product/boston-black-cav

http://www.crockettandjones.com/product/harvard-darkbrown-cord

Sanders:

http://www.sanders-uk.com/shop/product/madrid-9486td

Yeah, they are not a cheap option, what size are you? Will keep an eye out.

Sancho  E is a wide fit the same as a UK G. In the US a D is a medium or the equivalent to a UK F.

^ when you gotta dance , you gotta dance !!!

Last I checked btw, there were two pairs of made-in-US Weejuns on eBay in your size; which coincidentally happens to be my size too. They looked to be 80s and early 90s (still made in Maine) era from what I could discern; color 8 and black, respectively. I think one pair may have already sold. I'm after a pair of pre-80's original brown Weejuns for myself.

Oxblood:

http://www.barnetsshoes.co.uk/images/_lib/lorens-501-3-mens-gents-leather-burgundy-loafer-3014154-0-1398705081000.jpg

Sancho, the width depends not only on the look you are after but also on the width of your feet... Sebagos are generally a bit clunkier, even in B width (narrow) - the widths in US sizes are:

A - VERY narrow (even a little bit too narow for me and I have pretty narrow feet)
B - narrow (my own width)
C - normal width, works on most feet (still can work on my feet)
D - normal slightly wider, works better with thicker socks on normal feet
E - wide
EE - wider
EEE - extra wide

So if the Sebago in D work for you sitting well on your foot, look out for D... wheras a C can work, too. Loafers can be tricky: they widen themselves very often due to a tight fit (loafers should be tighter, because of the lack of lacing), and then they get too wide which happens mostly on my own feet. But don't take anything else than D or C. If they sight very tight you can go up to E etc...

It really depends on your price range, too. Out of the suggested shoes the Crockett and Jones are probably the highest quality using the best leathers and they are also Goodyear welted, but such loafers are so expensive you should look out for them locally and only get them after trying them on and knowing they are the best fit...