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If the cells are designed for laptop use, that is generally between 0.5C and 1.5C so you'd need to put a whole bunch in parallel, which poses problem of its own. Not all cells are equal, there is some variance, so putting 2 in parallel won't necessarily mean the current is split exactly 50/50. You have 10 in parallel and you can be almost certain it's not going to be 10% current going to each individual cell.

Also be careful with charging, Li-Ions charge to a diffferent max voltage than LiPos do. It's not 4.2V. It might be 4.1V, or it might be lower, depends on the cell chemistry.

To test the load-carrying capacity, get two 1-ohm power resistors. Measure the open-circuit voltage. Then measure the voltage with a single power resistor load. Measure it with both power resistors load (in parallel). Use the voltage-divider formula to find the 'hidden' or 'virtual' internal resistance of the battery. From this, you can calculate the theoretical voltage drop at higher C ratings. The 1-ohm resistor is approximentally a 1.5C drain for these cells, if the voltage drops even 10% (ie. 4V to 3.6V) that would make them pretty useless for a high-drain application.