If I was you, I would drill all kind's of holes into wood, perhaps porous, half rotten wood, things like, material what our native bees
would find in the wild, hang them up on trees walls etc.
This way you will have some bees what stick around your area.
Also, make some nesting sites for bumble bees, you should find ideas on Google, I had some attracted by a little box, see video link.

Konrad

Here is a link that might be useful: Bumble Bee Video

here is a link to an alternative pollinator forum on beesource.com

This should help you make a decision

Here is a link that might be useful: http://www.beesource.com/forums/forumdisplay.php?f=265

The more varieties of bees (honeybees, mason, miner, hover, etc.) you can attract, the more types of pollinating they can do. Not all bees pollinate the same blossoms.

You might find suggestions and information at the Xerces site.

For more bee and pollinator links, feel free to visit my Bee Sanctuary blog.

Good luck and hope you attract many bees! :-D

Kris