A quick visit to the Piko website shows that Piko are not attending the usual Nurnberg Toy Fair, which from memory is held in February. One may ask if the toy fair is another victim of circumstances in that fair city? Next question is when Marklin will release its intended release items (not the simply rereleased ex-LGB planned releases).
Tim,
The NTF 2008 is from Feb 7th through 12th.
You can look up a list of exhibitors on their site. PIKO exhibits in Hall 4A Booth F-204
This link http://www.spielwarenmesse.de/index.php?id=405 is straight to the selection of exhibitors. 
The PDF http://meiller.spielwarenmesse.de/md18/spielwarenmesse/daten/spielwarenmesse_2008/hallenplaene/pdf/4A.pdf is for the MRR hall.
Happy browsing!
HJ,
this is taken from their website, press release dated 16 January, 2008 -
Hi PIKO fans!
In 2008 you will have the opportunity to visit us at the following fairs. You are welcome to visit the fairs and to stop by at our booth where we will be glad to inform you about our new releases. We also offer a few fan articles at our booth.
March
13. - 16.03.2008 Faszination Modellbau in Sinsheim
April
16. - 20.04.2008 Intermodellbau in Dortmund
October
03. - 05.10.2008 Modell & Hobby 2007 in Leipzig
October/November
31.10 - 02.11.2008 Modellbau Bodensee in Friedrichhafen
November
06. - 09.11.2008 Internationale Modellbahn Ausstellung in Köln
November
13. - 16.11.2008 Modellbau in Stuttgart
Tim,
In Germany you have to differentiate between the shows open to the general public and the Nürnberg Fair which is supposedly reserved for the dealers, buyers and others directly associated with the trade. 
The ones listed by you are the shows for the general public.