Dear Sir,
You say: "The unit vectors i, j, and k represent the x, y, and z axes respectively. The unit vectors make it possible for the axes themselves to be a part of computations". In that case why complicate things by adding terms i, j, and k? The x, y, and z axes could have been sufficient by treating them as unit vectors. After all, vectors are different only because they have movement (energy) and direction. The axes provide direction. The axes have no meaning without something to represent. We also use mobile coordinates. Thus, what is the justification of adding i, j, and k? Further, x, y, and z are real, whereas i, j, and k satisfy i^2 = -1, which means complex. Why should we use complex numbers at all? They do not have physical presence. Anything that has no physicality cannot be a part of physics. Your statement that you have tried to "combine physical space, in the form of an arbitrary unit vector, with the complex plane..." presupposes that both do exist physically. Is there any proof in its support? Can you give examples?
Your statement: "Let x = 1 and let y = 1. It follows that x y = 2. This is a simple scalar result. Now let x = i and let y = j. It follows that x y = i j. This is a vector from the origin of length sqrt(2) at an angle midway between the x and y axes" only conforms our views. Addition is linear accumulation, which is possible between similars. Here x and y have the same value and belong to one class. But x = i and let y = j shows that they belong to two different classes. You cannot add 5 oranges and 3 apples. You can add them only as fruits. We have submitted an essay to physically explain 10 dimensions. Unlike your 5 -D inferred space, we have shown direct correlation, where we have used the same logic as you have shown here.
Regards,
basudeba