Alternatives other systems

Hi all,

I looking for a Support System, i have been trying a lot...i would like comment my ideas if i cant get some feedback.

- I think OTRS is the most powerfull suppor system, but it have got some problems like: hard theming, no xml,no integration, no mobiles views,..
- tenderapp.com or zendesk.com, they are SSO, dont free software and dont instalable...so discarded.

I would like some between this systems, i thinking to do it with drupal + support + themes (like openatrium) ... any suggest??