Though I had no chance to try it yet on the real boxes, I think it's great idea:
When you have LOTS of real servers in the LB pool, and every one of them has several ports to healthcheck, some of them can flap from time to time.
After surfing through couple of network mailing lists and manuals (of course, btw these smile theme in Multiply is quite funny), this all came to one possible solution of the problem:
For example, I have several real servers with http and 8080 ports configured, if one port fails due to healthcheck I want the server out of the pool. All this is possible, when you use Boolean healthcheck policy, fantastic to my mind, and I have no idea, why we haven't used it in our net.

So here we go:
1) First of all, we create http match-list, which checks the page for certailn string:
http-match-list
default down
up simple "OK"

2) Create healthcheck for the primary port that will bring down the other ports if it fails:

healthchk policy1 tcp
dest-ip 10.2.3.4
port http content-check m1
port http url "HEAD / HTTP/1.0"
l7-check

3) Then we create healthcheck policy for the secondary port:

healthchk policy2 tcp
dest-ip 10.2.3.4
port 8080 content-check m1
port 8080 url "HEAD / index.htm"
l7-check

4) Create boolean healthcheck for these two ports:

healthchk policyhttpdown boolean and policy1 policy2

5) Fix the real server config:

server real bannersite6 10.2.3.4
port 8080
8080 keepalive
port 8080 url "HEAD / index.htm"
port 8080 content-match m1
port 8080 status-code 200 299 302 302
port 8080
port http
port http keepalive
port http healthchk policyhttpdown
port http url "HEAD / HTTP/1.0"
port http content-match m1
port http status-code 200 299 302 302

That's all. Usually we use only status-codes for healthchecks, and I don't know yet if it's possible to use it altogether or use codes instead of content-match, which I don't really like.

UPDATE: Seems like it's possible to use codes only.

So, all I need is to test it))))