Kylie:
Thanks for the suggestions, but none of them really fits the bill. I am looking for a 16 gauge with at least 28 inch barrels, a straight grip and splinter for end, preferably weighing no more than 6-1/2 pounds or a bit less. Not as easy to find as one might think.
Rem
The six and a half pound max weight will be the real killer. The Spanish tend to prefer, and prefer to make, medium game guns so the vast majority of 12 and 16 gauge guns will weigh right around seven pounds. Any of the makers would be happy to make up whatever you want, but at present that's going to run you somewhere in the $10k to $20K (USD).
Good luck with your search!