Many of the Traveller games that I have run have involved players raising and training mercenary units. In those games a serious problem has often arisen, namely, that the expense of transporting the mercenary unit personnel has very often exceeded the fee for the job. If players try to finance their own vessel, they'll find that this is not generally cost effective either. For example, the principal and interest cost of bank loan on a Mercenary Cruiser in Classic Traveller eats up most or all of the fee for the "ticket" presented for the adventure found in "Broadsword." Even when the players did own a ship of some sort, it still cost 2000cr per person per month for life support to transport their troopers.
In Classic and Mega Traveller the solution to this problem was to convert a small merchant vessel or construct a small starship with a large portion of its volume dedicated to low berths. In this way, a fairly decent sized unit could be transported economically.
There is, however, a problem with this solution if you are using the T4 rules. While in CT/MT having a doctor (Medic-3+) eliminated risk of dying in low berths, in T4 that is not the case - at best one still dies on an 11 or 12 on 2d6 (1/12 chance)! Thus, carrying your unit in low berths guarantees a level of attrition that the troops just would not stand still for (and hopefully the PC's wouldn't either).
The first part of the solution to this problem is to use the "bunk" accommodations from the ship design sequences. Troops, in most of the ship design versions, are about the only folk that can be housed using "bunks. A bunk takes 1 displacement ton of space for 1 man, at 5000cr to build. A small stateroom in double occupancy can house 1 man for 1 ton volume but costs 20,000cr per man to build. The bunk then is the cheapest way to squeeze a large troop unit into your custom made mercenary transport or converted Far Trader.
However, you still are stuck with the expense of paying 2000cr per month for life support for each soldier transported. This can be ruinously expensive, especially when compared to the base salary for a private trooper of only 250cr per month plus shares. The solution to this expense is the use of the so-called "fast drug". Fast drug slows metabolism at a 1 to 60 rate, therefore you could say that you would need to spend 2000cr per 60 men at most (but perhaps per 30, to be more reasonable) for life support. If you choose the 1/30 ratio then life support would cost about 150cr per man.
The advantage to the commander/owner of unit is obvious in the money saved. The troops get a benefit as well since they get paid for a full month while subjectively only 12 honors have passed, and of course they avoid the danger of death in the low berth. This plan might also appeal to colony transports and refugee ships as well.
Why then don't we have these bunks in place in all merchant vessels? First of all the availability of the drug may be a problem, since you would probably need a doctor to prescribe and dispense it, and it would only be found above a certain tech level. Secondly, you still have to feed "fast" passengers, and you must have someone watch over them since they (very slowly) eat and walk around. Third, if, by accident, your trip lasts past the duration of the drug, you would suddenly have a huge drain on supplies endangering the crew. Lastly, the low berth allows transport across a long distance with only 1 possible complication, while Fast passage requires constant maintenance.