In reply to goldmember:
The Scottish Running Guide website has good race listings:
http://scottishrunningguide.com/
It's a wee bit incomplete at the moment, but keep checking back.
You can also get a listing on the Scottish Athletics website:
http://events.scottishathletics.org.uk/events
If it's early April, the Jim Dingwall 10k at Grangemouth is fast and flat, but not very attractive. The Tom Scott is a nicer 10 miler in Strathclyde Park.
For a bit of day out in May, you could get the boat to Cumbrae and do the Millport 10 miler.