The only two Tim/Tony one's that I know of are Shetiger's and Bananacosmic's and they are both two of the most amazing Tim/Tony fic's I've read.

All Is Fair by Banana Cosmic
http://bananacosmic.livejournal.com/93857.html?view=928161#t928161
Damage Over Time by Shetiger
http://shetiger.livejournal.com/614827.html

And then there is Tim/Tony/Gibbs Acting On Impulse by Taylor Gibbs

http://www.ncisfiction.com/chapters.php?stid=04514

and it's great as well!