The most recent version of Skype in my LANDesk defs in version 5.6. There has been a 5.8 available since 2/2/2012 and the most recent is 18.104.22.168. Versions older than 22.214.171.124 are vulnerable to an unspecified security vulnerability, so I'm wondering why LANDesk hasn't released an updated definition?
LANDesk is really good about adding content if requested. Of course there will be limitations to some items due to licensing, etc.
To request an item be added, you should open a support ticket or contact your support rep if you have one. We have a TAM and have had him request content for a few things and most if not all have been added.
This community site is not usually a great place to request such things as it is 80 - 90% user to user (my guesstimate) though some LANDesk employees are on here regularly.
You could also add your request to the "ideas" / Request area, where it may or may not get attention
I do not like to 'abuse' our TAM support by requesting some of the things I see posted here, but in cases like Skype, where we patch it and I noticed via this thread it was not updated, I had no qualms pinging him on it.
I have also been working with an inside contact I have to get "Auto Updates" disabled on certain patches such as Java, Flash, iTunes or at least configurable via LANDesk content, but again, I try to not push it