I have been considering breeding other types of Arabians (sea/polish/shagya/etc) into my Straight Spanish Arabians and going with a line of plain Arabians from here on out but blended with all the different types of Arabians other players have to offer. I guess I just am looking for someone to give their opinion on this. Would it be considered offensive to the other Arab breeders If I were to mix your lines with mine? 

It wouldn't bother me and is something I did with my seas and Arabian.

i wish more people would. especially for crossable breeds

I don't breed arabs, but I don't think it would bother me!

I don't see why anyone would be bothered by it, since it wouldn't affect their own lines. If someone bought a G.S.D. pup from me and crossed it to make whatever, that's their business, not mine, and wouldn't harm my line.