Modifying Melee Weapon: How to make a melee weapon with a telescoping handle?

[Varyon]

In GURPS: Martial Arts, on page 218, is an option called Trick Weapons. This is meant to represent things like retractable sword blades, but I think using it for a retractable handle would work fine. That gives a +2 to Holdout, which implies that it cuts the length of the weapon in half (+2 to Holdout would correspond to -2 to SM, which means half size) while retracted, and is +50% to cost - or +0.5 CF, using that system.

So, I would say you could design the weapon at its full length, apply a +0.5 CF to cut the length in half, another +0.5 CF to cut the length in half again, and so forth, until you reach the minimum size of the weapon. Realistically, the weapon should probably count as Cheap for breakage purposes, but in a Fantasy setting with a lot of magic, you can probably ignore that.

For example, let's say we want a staff that can be anywhere from 1 yard long (a baton) to 64 yards long. Based on the statistics of staves of various sizes, I would say that 1.5 lb and $5 per yard of staff is probably about right. So, a 64 yard staff would weigh 96 lb and cost $320. It can be reduced to half length up to 6 times (64->32->16->8->4->2->1), for a total of +300% or +3 CF (x4 to cost). The weapon would therefore weigh 96 lb and cost $1,280. If that's too heavy - and it probably is - I believe there are enchantments available to reduce a weapon's weight.