Probably not a Sabreliner. Looking closely at the art (by Keith Ferris, no less!), the fuselage cross-section looks to be circular, and judging by the crew, about equal to the diameter of a Lear 23. The windshield is much larger in proportion to the fuselage than on the Sabreliner (but is inspired by it). Also, the wing trailing edge is kinked, not a Sabreliner feature. I'd guess this to be a piece of Ferris industrial art (before he started painting giant murals in National Museums) illustrating a notional design. If he was supposed to illustrate a modified Sabreliner, he missed the mark, which I think is unlikely, given his well-earned reputation for accuracy in technical illustration.