Is there any way to determine if a book format is the smaller standard size versus the larger "Trade" paperback size? Thanks!

if you search by ISBN, Amazon will often (but certainly not always) have the actual dimensions of the book.

You can also look under "More Options" "Edit Book Data" for book dimensions.

It might not always be there or it might not be accurate.

It is possible for the same ISBN to be on both formats so even looking around and finding what it is listed as in some places won't guarantee it. "Paperback" listing can hold either as long as the ISBN matches. Printing companies are getting better, but there are still a lot out there with the same ISBN on multiple. I own one book in trade, mass market, and book club hard cover and they ALL have the same ISBN.

Mark - no there aren't...

The problem (not that there is a "Problem") is that an ISBN iis not a UPC number. 
It might be used as a UPC by some stores but it is not a UPC.

An ISBN is a 10 or 13 digit code number issued (for a price) that codes the title/author/type of book (preferably HB/Trade/Mass) publisher etc.
It is (was) hoped by the ISBN folks to be a different number for each and every type of book made  - a different number for type (HB/PB etyc), publisher (which may or may not change), Revisions, year published etc etc. For details just go to ISBN dot Org. They are in the business of issuing and selling ISBN's for money. 

The reality is - you do not need a ISBN to sell a book (it helps a whole lot but thats another story). You do not need a new ISBN when you republish a HB into a PB. (wether Trade or Mass). An ISBN is a business thing, not a government thing.

ISBN's cost $MONEY$ - upfront - some business buy them in bulk (discount) and 'sell them to me and you for $60 to $120 (and up).... some authors and or publishes do not want to spend money for new issued ISBNs and will recycle the existing ISBN when they make a HB into a Trade or Mass - why? because they can (and do). Its usually a business decision - 

A UPC is (generally) a very unique 12 digit code number that (generally) differentiates between different sizes of the same product (10 oz vs 16 oz).
 

This has been a topic of discussion many times here in the forums - just goto the top of this page and select "Search All Forums" and put in ISBN into the search box.

Good uck with finding what you are truly looking for..