Hmm...

You could build a 6 meter array of verticals, a four square or a
rectangle array or something. It may be a little touchy to adjust for
proper phasing, but it could be done if you've got your heart set on
phased verticals. You're not going to find a commercial phasing box
for 6m though. The only commercial transmit phasing unit I know of is
this:

http://www.dxengineering.com/Parts.a... o=DXE-TFS-1P

And it's for 160, 80, 40...

If ice survival is your only concern, maybe you should just add heaters
to your yagi :-)

Good luck...

Dan
N3OX