You are asking a lot from the 5800, but unless another user has a similar home and is using a PA 5800, or a DS7000 (which has a similar receiver), I doubt you will get anything more than "guesstimates" from other forum members. You say you have "lots of brick walls". Do you have brick walls which might be between the 5800 console and the pendant when it is triggered? Do you expect the pendant to work outside the house? How far?
Why don't you just buy one directly from X10.com through their telephone sales. It is simple to set up.
Explain your situation and ask the sales rep to note this on their internal order, so there will be a record of your concerns. You have a 30 day "no questions asked" period of return, when purchased directly from X10 and not Ebay or other outside vendor. 30 days should give you enough time for thorough range testing.
My "guesstimate" is: NO, you will have dead zones.