Hello,
Just to share this information, I used so far M1306B and now I found a good replacement with Maestro Wireless M100 that I buy from there:
adm21.fr/index.asp?ID=467&IDF=98
Cheers,
I’m sure it’s a great replacement in many cases, but note that the IO pins in the 4-way Microfit connector are different - so it may not be usable for an application that relies upon those pins… 
If I remember correctly, the price I was offered in the UK was higher than I could get the M1306B at the time - and the Fastrack Supreme…
See also: viewtopic.php?f=53&t=3027&p=11094#p11094