Bushmaster will do a 1/7" upper if you call them up - you may have to wait (or so I have read on another forum).
I have a 14.5" 1/7" LMT upper, chrome lined/w M4 feed ramps, permanent phantom I am very happy with. I got it from
www.jtacsupply.com - quick turn around.
http://www.adcofirearms.com also carries them, they will add a permanent phantom FS to a 14.5" if you are looking for a total length of 16" for non-NFA. I have made a number of orders for parts, stocks, etc and have been happy with their service.
http://www.bravocompanyusa.com carries LMT uppers as well, but are currently not offering a 14.5" option/w permanent phantom FS. I have placed one order with them which they turned around quickly and communicated via email the 2 day delay because the magpul stock I ordered was temporarily out of stock.
Also, this place
http://www.cmmginc.com has M4A3/A4 uppers 1/7", chromelined, M4 feed ramps and these uppers have received good reviews. I have not ordered from them, but did exchange some emails and they answered my queries. If I ever feel a need for another 14.5" upper, I'll go this way.
All of the above will do 16" with A2 FS too.
The 1/7" twist and M4 feed ramps are not "must haves" but I get them if I can. 1/9" will handle up to 70 gr bullets, and most will handle up to 75 gr. I really do like chrome lining (for a blaster, CQB, etc) as it adds to the durability of the barrel, so I look hard for that option. All the above qualify there.
I currently do not recommend Colt as it seems they have decided to take an official position to not offer "EBRs" to civilians. Not a suprise since they started doing away with FS on their rifles prior to the AWB.