Re: Can members of the crocodilians interbreed and produce viable offspring?

What a great question!

Quickly, yes it is possible, but only between two SPECIES, certainly not 
between genus, or families.

First, a quick lesson on taxonomy:

Organisms are classified by scientists according to the KPCOFGS (King 
Phillip Comes Over For Good Scotch!) principle:

KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES

Crocodilians are classified as follows:

KINGDOM: Animalia
PHYLUM: Chordata
Class: Reptilia
Order: Crocodylia
Families: Alligatoridae (Alligators), Crocodylidae (true Crocodiles) and 
Gavialidae (Gharials).
Genus: x
Species: X

I have heard of hybridization between some crocodile species:

(1) Cuban crocodile (Crocodylus rhombifer) X American crocodile (C. 
acutus).
There are management implications here because both these species have low 
populations (especially the Cuban). Hybridization reduces population 
numbers even further.

(2) Siamese crocodile (C. siamensiS) X Saltwater crocodile (C. porosus).

These examples are similar to your lion X tiger idea - Panthera leo and P. 
tigris - both are of the same genus.

I can't see hybridization occuring between say a Gharial and an Alligator 
though. They're of totally different families!

That would be like crossing a Bobcat (Lynx rufus) with a Jaguar (P. onca)!

I hope this explains the situation a little more clearly.