No there isnt really a problem with aspen shavings but sometimes shredded aspen can get into their noses and ears and stuff. With babies your best off using towels and sheets.
As for where to buy from, look at the bts.net classifieds. I highly reccomend Ray Gurgui. I believe he still has some Northerns, Easterns, and Tanimbars available.

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1.0 Indonesian Blue Tongue Skink (Don)
1.1 Irian Jaya Blue Tongue Skink(Sammy) & (Sausage Girl)
0.0.1 Tanimbar Island Blue Tongue Skink ( Spunky Sebastian)
0.0.1 Ornate Uro (Spike)
1.0.1 Green Tree Pythons ( Male=Floyd, Baby= Verdi)
0.1 Western Hognose (Piggy)
0.0.1 Egyptian Tortiose(Tank)
0.0.1 Sonoran Gopher snake ( Toro)
0.1 Albino Leo gecko (Sasha)