Is there a security proof for the Triple-DES construction in the ideal cipher model?
Yes.  The following papers should be exactly what you are looking for.

The following paper shows that the answer is "Yes" and provides evidence that 3-key Triple DES is more secure than single DES:


Code-Based Game-Playing Proofs and the Security of Triple Encryption.
Mihir Bellare, Phillip Rogaway.  IACR ePrint 2004/331.  (Full version of a paper published at Eurocrypt 2006.)


They show that, in the ideal cipher model, the adversary must make more than about $2^{78}$ chosen-plaintext/ciphertext queries to have a reasonable chance at distinguishing 3-key Triple DES from a random permutation.  This not too far off from the best known attack on 3-key Triple DES (which requires about $2^{90}$ queries), and shows that 3-key Triple DES is significantly more secure than single DES (again, in the ideal cipher model).

There is prior work by Aiello et al. that analyzes 2-key Triple DES in the ideal cipher; see the related work section of the Bellare et al. paper for a citation and discussion.

There is also subsequent work that re-proves the result on 3-key Triple DES in a simpler form, and analyzes 5DES and longer cascades as well:


Cascade Encryption Revisited.
Peter Gazi, Ueli Maurer.  Asiacrypt 2009.