A fuel cell assembly comprising: a plurality of fuel cell bundles, each fuel cell bundle comprising: an array of elongated tubular fuel cells comprising a plurality of rows of spaced apart, elongated tubular fuel cells; a plurality of elongated electrical connectors each having a first contact for coupling with a first fuel cell and a second contact for coupling with a second fuel cell and wherein each of said electrical connectors is disposed between at least two of said elongated tubular fuel cells; an oxidant supply system; a fuel supply system; and a support structure for integrating as a bundle said fuel cells, said oxidant supply system and said fuel supply system, wherein said support structure comprises an elongated tubular fuel cell support/spacer plate and an oxidant feed tube support/spacer plate; wherein the elongated tubular fuel cell support/spacer plate is spaced from and connected to the oxidant feed tube support/spacer plate by one or more first pin-in-sleeve combinations each of which is connected to a first side of the elongated tubular fuel cell support/spacer plate and to a first side of the oxidant feed tube support/spacer plate. The fuel cell assembly may also comprise flexible members defining open slots on electrical connectors. Flexible power leads with cross-over plates and tabs may also be comprised in the fuel cell assembly.