Try the RAF Chaplains' Website (link below). There are some serious ones and some not so serious
. (Some along the lines of the ones above!) You can always pic and mix. IMHO the best ones are short and sweet but funny.
http://www.raf.mod.uk/chaplains/publications/graces.doc
If you find a good one, pass it on - I'm doing a grace at my sister's wedding later in the year after I do their ceremony for them.