My colleagues here at the Cancer Research UK Manchester Institute amplify the starting RNA samples using the EpiStem RNA-Amp kit to generate microgram quantities of cDNA for RNA-Seq etc. We have found that the amplified cDNA yields results that correlate strongly with unamplified data: https://www.researchgate.net/publication/269695199_Evaluation_and_validation_of_a_robust_single_cell_RNA-amplification_protocol_through_transcriptional_profiling_of_enriched_lung_cancer_initiating_cells
Article Evaluation and validation of a robust single cell RNA-amplif...
The kit I use takes as little as 0.5 ng RNA, although I only used it with 3-10 ng range of input RNA. It is from Nugen and called Ovation RNA-seq System V2. Make sure you get the "V2" as it is much improved over the original kit.