So, just if anyone is interested. I found those front and rear mudguards for the 19's and up 500's and 750's from a parts supplier in the UK. I got the part numbers and plugged them into one of the US on-line parts distributors and up they came. I dont know what kind of back-order delay there will be on them (if any) but I'm in no rush. This parts supplier has always come thru for me, never a bad experience. The mudguards, or more like fender extenders, were reasonably priced (22 bucks a piece) and the shipping was peanuts compared to shipping from Europe. If anyone is interested, I can post the part numbers.
Judging by the pictures above and the UK parts diagrams, they are mounted to the existing fenders using the plastic push rivets. This would mean having to drill several holes thru the existing fenders. I'm really not very keen on drilling thru a perfectly fine fender and I also may not like the way they look or perform after putting them on so I will try to come up with a way to mount them without drilling thru the fenders. Maybe use some of that high strength body panel silicon style tape. I've used it before on non stressed plastic parts and it has never come off.