Are SSDs true random-access devices?
From Random-access Memory (Wikipedia):


  A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older magnetic tapes and drum memory, the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.


Based on this definition, I would argue that YES, SSDs are "true" random-access devices.  Access speed does not vary at all based on where on the media a particular bit of information is stored.  The reason SSDs are faster at sequential access than random access has nothing to do with the underlying NAND, but rather its because the controller can always access all NAND dies in parallel, whereas for a random workload this is statistically unlikely.  Also, a smart controller can detect that you're doing a sequential workload, and start reading data ahead of what you've asked for yet.  However, this only applies to large-block access, so if you're accessing a specific byte at a time, you won't be able to take advantage of this parallelism anyway.  At the NAND level, the sequential reads take just as long as the random ones, it's just that you can start the next one before the first one finishes.