Thanks Pepin for posting pics.
Rolf, the photo's I had in mind are the last of the line up on the beach (Zandvoort 07) and the last spi photo (Mumbles 08).
In the line up photo you will need to concentrate on the leech of sail No 801 (Paul's Landy mainsail) and the one directly behind 111 (Hans's Landy mainsail). I can assure you that Hans's leech is more convex.
As for the spi's I've never seen a Landy spi on either a Stealth or Blade with such a high angle cut between the tack and clew. Maybe it's my imagination! but having raced and seen a lot of Landy kites Hans's just appears different for some reason. Hence I would be shocked if it wasn't a Landy one off. If it isn't then somebody braver than me should tell Hans to sheet in and go higher[;-)]

My Inter 17 had Pink Spi's (2 made by Grant) and so I needed an change of colour scheme. Next one might be Pink!!!!!

Not only does Landy do various designs there are also various material options;
http://www.bitz-brands.com/acatalog/Formula_16.html
And if you're feeling really rich you could spend 12.8K on a mainsail!!

Are GP pricing on the web ?

No. A spi is £500 + VAT and I was quoted a while back £850 + VAT for a main (without the battens). VAT is 15% here in the UK.

GP recently quoted me:

Mainsail £975 plus vat
Main batten set £150 plus vat
Jib £295 plus vat
Asymmetric £485 plus vat