There isn't one, you need to upgrade to 10.5
Is there a work around for this? not sure why I can program a 7821, 7841 and 7861 but not the 7811. Can I install the device pack for 9.1 or 10.5 to get it to work?
No, even if you tried that, it would simply error out as DevPacks are version specific.
I'm not a fan of this, but looks to be the case. For 7811/8811's you'll need to upgrade to 10.5/11 OR downgrade to 8.5, 8.6, 9.x, etc...
The last I checked, 10.0 is a valid version, not EOS'd so it should get a device pack. The device support has long been one of the top features of call manager - and pushing upgrades for a device never goes over well especially when they've tied in IM&P to these upgrades.
No, that's wrong, only maintenance releases get DevPacks, and 10.0 is not a MR, in the 10.x train, 10.5(2) is the MR, and the one that will keep getting updates and DevPacks.
If you look at the link I posted, you'll see only MR releases get them. Which means 8.6, 9.1(2), 10.5(2), etc.