If you build a123 packs in multiples of 4s, you can easily use any number of the better SLA chargers, which all seem to use the same constant current/constant voltage (CC/CV...) charging profile found in almost all of the hobby chargers with a123-compatible charging modes. The main difference is that the SLA chargers have a fixed cutoff voltage and with the RC chargers, you need to select the number of cells in series, which then determines the cutoff voltage.
A typical 48V SLA charger has a cutoff voltage of about 58V. It will charge a battery at the max current until the voltage reaches this level (CC mode...) and then holds this voltage while the current gradually get reduced (CV mode...). Generally, when the current drops below about 10 percent of the max charge rate, the charge is complete. In any case, a123 cells have an optimum CC/CV voltage cutoff of 3.65V, so a 16s pack setup needs a cutoff of 58.4V. This works pretty much across the board, so an 8s a123 pack will work with a 24V SLA charger, a 12s with a 36V version, etc.
There are two other issues with using RC chargers. One is they typically are only good for 180-200W, so even if they allow up to 10-12s setups, the max charge rate is limited to about 5A. The other is that they all are designed to work off a 12V input, so you still need a good power supply to use them at home. I use a 25A model from Radio Shack with two Thunder Power TP-1010C 10-cell chargers and "matiching" TP-210V auto-balancers and this setup works quite well. The balancers are linked to the chargers with serial cables, which allows the charger to monitor and display voltage levels for each block of cells.
Getting back to your question about how to do a 30s4p setup, I really think you need to break this down to sub-packs, to make the charging and balancing "managable". If it were me, I'd do six 10s4p subpacks. You would use them 3 in series and 2 in parallel. You could have a charging harness that would let you charge them in 10s blocks, either using three chargers/balancers or you could do it with two chargers and a harness that connected the packs as two groups of three packs in parallel.
I'm doing a new a123 setup that will use the cells pretty much just how they come out of the DeWalt packs. By keeping the plastic end cases intact, all the balancing connections are available in the two 5-pin connectors that the DeWalt BMS plugs into, normally. I made a simple harness that plugs into these connectors and has standard balancer connectors on the other end. Here's what a 10s2p pack looks like:
Actually, what I'm doing now is making two 10s4p packs, using this method, which I will use in a 20s4p configuration on one of my bikes. I got some extra-wide shrink wrap that will cover a complete 10s4p pack. With the harnesses pre-made, it only takes about a half hour to do the whole thing.
What I'm also doing is making a 10-cell version of the LVC circuit that Bob Mcree came up with in one of the other threads. This very clever, and simpl, design will monitor the voltage of each block of paralleled cells. The circuit plugs into the "Brake Inhibit" input on all Clyte controllers. When any block of cells drops below 2.7V, the brake inhibit line trips, which causes the controller to cut power. The board I'm doing will have connectors that will plug into the balancer plugs on the pack. I will use two of these circuits, one with each 10s4p pack. The outputs can be"ganged" together and connected to the controller.
-- Gary
helloooo long charge time.. but i will rarely drain the packs flat... 
