Here's my collection of Epic 40k Tyranids. These models are out of production and sadly no longer available from Specialist Games at the current time (2008). You can still buy them second hand from e-bay and other sources, but expect to pay a premium, especially for the plastic infantry.
The Dominatrix, Supreme Commander of Tyranid forces
Hydraphant Front
Hydraphant rear view
Hierophants
Harridans 
Trygons 
Hive Tyrants
Warriors 
Lictors
Dactylis 
Exocrine 
Carnifexes 
Biovores
Zoanthropes
Haruspex (left) and Malefactors (right) 
Genestealers 
Termagaunts 
Hormagaunts 
Gargoyles 
Meiotic Spores (Once again 40k pieces that are suitable for Epic)
Nodes (scenery pieces from the 40k which are about the right size for these in Epic)