Hey everybody, thanks for all the information. I ended up getting in touch with a contact at Sizmek, and just like it was mentioned above, they are *very* GSAP friendly and do host GSAP libraries on their CDN - here are the links to TweenLite js files in case anyone needs them:
Sizmek CDN non secure
http://ds.serving-sys.com/BurstingcachedScripts/libraries/greensock/1_18_0/plugins/cssplugin.min.js
http://ds.serving-sys.com/BurstingcachedScripts/libraries/greensock/1_18_0/easing/easepack.min.js
http://ds.serving-sys.com/BurstingcachedScripts/libraries/greensock/1_18_0/TweenLite.min.js
Sizmek CDN secure
https://secure-ds.serving-sys.com/BurstingcachedScripts/libraries/greensock/1_18_0/plugins/cssplugin.min.js
https://secure-ds.serving-sys.com/BurstingcachedScripts/libraries/greensock/1_18_0/easing/easepack.min.js
https://secure-ds.serving-sys.com/BurstingcachedScripts/libraries/greensock/1_18_0/TweenLite.min.js
Thanks again!